With less than a year to go before the launch of NASA's Mars Exploration Rover mission, scientists have spent the last few weeks at a high-tech summer camp, rehearsing their roles for when the spacecraft take center stage.

"The purpose of this test is really to teach the science team how to remotely conduct field geology using a rover, rather than to test the rover hardware," said Dr. John Callas, science manager for the Mars Exploration Rover mission at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We sent one of our engineering development rovers out to a distant, undisclosed desert location, with the science team back at JPL planning the operations and sending commands, just as they'll do when the actual rovers are on Mars."

The 10-day blind test, which ran from Aug. 10 to 19, used the Field Integrated Design Operations testbed, called Fido, which is similar in size and capability to the Mars Exploration Rovers. Although important differences exist, the similarities are great enough that the same types of challenges exist in commanding these rovers in complex realistic terrain as are expected for the rovers on Mars.

"The scientific instruments on this test rover are similar to the Athena science payload that will be carried by the Mars Exploration Rovers," said Dr. Steve Squyres, principal investigator for the Mars Exploration Rover mission at Cornell University, Ithaca, N.Y. "We're using the test rover now to learn how to do good field geology with a robot. When we get to real Mars rover operations in 2004, we'll be able to use everything we're learning now to maximize our science return."

"The test rover has received and executed daily commands via satellite communications between JPL and the remote desert field site. Each day, they have sent images and science data to JPL that reveal properties of the desert geology," said Dr. Eddie Tunstel, the rover's lead engineer at JPL.

The Mars Exploration Rovers will be launched in May and June 2003. Upon their arrival at Mars in January 2004, they will spend at least three months conducting surface operations, exploring Mars for evidence of past water interaction with the surface and looking for other clues to the planet's past.

The science team of more than 60 scientists from around the world will tell the rovers what to do and where to go from the mission control room at JPL. This month's test is one of several training operations that are planned before landing.

The rovers are currently being built at JPL and will be shipped to the Kennedy Space Center in Florida early next year to begin preparations for launch. Shortly before the launch, NASA will select the landing sites.